Strait, sound, channel, passage, narrows can all denote a long and comparatively narrow stretch of water connecting two larger bodies.
Strait , often as the plural straits with either singular or plural construction, denotes a relatively short and very narrow waterway.
Sound applies to a longer and more extensive waterway than a strait; the term is often applied to a long passage of water between the mainland and an island or group of islands and therefore at each end opening into the same ocean or sea or arms of the same ocean or sea.
Channel is less frequent than strait or sound as a technical term in the sense here considered, but when it is so used it denotes a relatively large sound.
Passage is practically synonymous with channel , denoting a connecting body of water wider than a strait.
Narrows designates a strait or a contracted part of a body of water; it is especially used of the necklike part of a bottle-shaped harbor.